4-5
4.2 MOTOR DRIVE TIMING
The phase of motors and the thermal head need to be synchronized to print.
There are two driving modes, high speed print mode for high speed printing and standard print mode for
high print quality.
Select either of the two modes according to the application.
Basic pulse width of the motor drive pulse, Tm, is a value (unit: msec) obtained by multiplying by 1000 the
reciprocal number of the driving frequency calculated using formula 1 of “2.3 Paper Feed Characteristics”.
[High speed print mode]
In high speed print mode, the head drive and the motor drive are executed independently of each
other by separating 13 blocks constituting one line into arbitrary groups each time one line is printed.
This independent drive of the thermal head and the motor makes print speed highest when one line
(corresponding to two phases of the motor) is printed in one group. When one line is printed in more
than one group, however, because two phases of the motor constitutes one line, dots of the same
block may be printed either in the 1st step or in the 2nd step, or printed in the 1st and 2nd steps,
causing poor print quality.
•
Pause State
Transfer the print data to the thermal head according to “4.1 THERMAL HEAD DRIVE TIMING”.
•
Start up phase
Excite the previous phase of pausing motors. The step time should be Tm.
•
1st line
Drive the motor by one step (1st step). The step time should be the accelerating 1st step time or
Tm, whichever is longer.
Input the selected block data to the thermal head and set DST to high in synchronization with the
motor drive.
After setting DST to high, set DST to low when the driving time calculated in “2.6 CONTROLLING
THE HEAD ACTIVATION (DST) PULSE WIDTH” has passed.
When there are blocks for which driving is not completed, print 1 line by repeating the input of the
selected block, setting DST to high and setting DST to low after driving is completed.
Transfer the print data of the next line to the thermal head after completing 1 line of print. Drive the
motor by one step (2nd step) regardless of whether DST is high or low (during thermal head driving
or not) after completion of the motor's 1st step. The step time should be the accelerating 2nd step
or Tm, whichever is longest.
Move to the 2nd line after driving all blocks, the transfer of print data for the next line and the 2nd
step time of the motor.
•
2nd line
Drive the motor by one step (3rd step). Since the 2nd step time of the 1st line changes depending
on the contents of the print, the 3rd step time should be the next acceleration step time nearest to
the time of the previous step or Tm, whichever is longer.
Summary of Contents for LTP3445
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